In-situ grown rod-shaped Ni(OH)2 between interlayer of g-C3N4 for hydrogen evolution under visible light

[Display omitted] •g-C3N4/Ni(OH)2 photocatalyst was synthesized by a simple hydrothermal method.•CO groups were introduced on the surface to enrich electrons.•The heterostructure between the rod-shaped Ni(OH)2 and g-C3N4.•CN-Ni2 composite showed superior photocatalytic hydrogen evolution efficiency.•QE of CN-Ni2 composite sample achieved 2.78% under light at λ = 420 nm. Non-noble metal g-C3N4/Ni(OH)2 photocatalyst was successfully synthesized by a wet-chemical method. The morphology, structure and photocatalytic hydrogen evolution of g-C3N4/Ni(OH)2 were researched. The experiments showed that the best photocatalytic hydrogen evolution of g-C3N4/Ni(OH)2 was 21 μmolg-1h−1, which was about 105 folds than that of pure g-C3N4. And that the apparent quantum efficiency (AQE) of g-C3N4/Ni(OH)2 composite (2 wt%) achieved 2.78% under light at λ = 420 nm. The enhanced photocatalytic performance can be attributed to the heterostructure between the rod-shaped Ni(OH)2 and g-C3N4. Meanwhile, partial carbonylation on the surface of g-C3N4 via hydrothermal reaction has made a certain contribution. Their synergistic effect promotes the rapid transfer and separation of electron-hole pairs, and improves the efficiency of photocatalytic hydrogen evolution. The possible mechanism of hydrogen evolution was also proposed.